XBP1 and fatty liver disease: Cheng et al. [38] established a transgenic MKR mouse model of T2DM with fatty liver by feeding the mice a high-fat diet and found that the TG and fatty acid levels in the liver of the model mice were significantly increased, and ERS markers GRP78, X-box binding protein 1 (XBP1), fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC-α), and glycogen synthase kinase (GSK3β) mRNA expression levels were increased, which indicated that ERS was involved in regulating liver lipid metabolism and played an important role in the formation of fatty liver in T2DM.